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    BGA Station - having some problems with profiles

    Hi guys so the BGA rework station finally arrived yesterday.

    I came very well packed but without any instructions. I had to refer to a couple of videos showing these machines working on youtube to figure out exactly which bit went where, but now I have it all put together

    I did ask the seller for a user manual yesterday and today I have an English user manual PDF for the LY G720 in my email

    It looks a nice well built machine. I have played around with some scrap boards with BGA and QFP chips on them but so far I haven't managed to unsolder anything. I don't think there is anything wrong with the machine I think it is something wrong with me lol

    It came with about a dozen preloaded profiles. Some have chinese names but others such as Leaded 1 2 and 3, Unleaded 1 & 2 seem fairly obvious

    The problem I am finding is that the solder isn't melting even though the thermo-couple tells me the temperature is high enough for Lead Free to liquify

    Here's a few pics, and a video I've made of the machine in operation and showing what is going wrong

    Can someone point me in the right direction to fix this?

    cheers

    https://youtu.be/I9zIdQFAmSM
    Attached Files
    Last edited by dicky96; 12-12-2019, 09:41 AM.
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    #2
    Re: BGA Station - having some problems with profiles

    This is how it came packaged!
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      #3
      Re: BGA Station - having some problems with profiles

      Verify the temperature with a secondary probe and device.

      Is the solder liquefying and the Winbond is glued down ?
      Last edited by diif; 12-12-2019, 10:54 AM.

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        #4
        Re: BGA Station - having some problems with profiles

        Hi diif

        I've got two separate temperature meters and thermocouples, I'll try that tomorrow.

        No the solder did not look like it had liquified at all which is what is puzzling me. I accidentally cut the video recording off when I started poking at the QFP with my tweezers so you didn't see it - but the little discrete SMDs around the chip were still soldered solid as well.

        What do you think of the way the profiles drop the temperature during the last phase so the sensor near the chip drops by about 10C just before the vacuum pickup kicks in. Is there some reason for that?

        I browsed a few different profiles on the machine and they all seemed to be set to do that, like it's normal.

        I've attached the instruction manual pdf. It has examples of 'commonly used BGA profiles' at the end. Maybe that info will be useful to some folks here to use with other BGA stations

        I've tried a BGA chip on an old satellite receiver PCB as well as that QFP. It would be unlucky if both were glued down I think.

        I can't modify the profiles at the moment - I realised I need to log in as admin on the BGA machine and there is a password which I don't have. I've asked the seller for that but given the time difference it will most likely be tomorrow before I have that.
        Attached Files
        Last edited by dicky96; 12-12-2019, 11:44 AM.
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          #5
          Re: BGA Station - having some problems with profiles

          No idea why the bottom hater drops off, incorrect programming of the profile perhaps ?

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            #6
            Re: BGA Station - having some problems with profiles

            I will watching this post
            9 PC LCD Monitor
            6 LCD Flat Screen TV
            30 Desk Top Switching Power Supply
            10 Battery Charger Switching Power Supply for Power Tool
            6 18v Lithium Battery Power Boards for Tool Battery Packs
            1 XBox 360 Switching Power Supply and M Board
            25 Servo Drives 220/460 3 Phase
            6 De-soldering Station Switching Power Supply 1 Power Supply
            1 Dell Mother Board
            15 Computer Power Supply
            1 HP Printer Supply & Control Board * lighting finished it *


            These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

            1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
            2 Hem Saw Computer Stack Board

            All of these had CAPs POOF
            All of the mosfet that are taken out by bad caps

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              #7
              Re: BGA Station - having some problems with profiles

              OK, I've emailed Wayne at LY to ask him to view the video and advise me on what is causing this behaviour. Due to time difference it could be a while until I get a response.

              He gave me the admin password so I can play edit or create profiles now.


              Rich
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                #8
                Re: BGA Station - having some problems with profiles

                Did you verify the K thermocouple is accurate with a secondary device/probe?
                You could try running a profile with a piece of leaded solder placed on the PCB. You'll be able to see what temperature it melts at which you can verify against its data sheet.

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                  #9
                  Re: BGA Station - having some problems with profiles

                  Hi guys
                  I tried this morning with a separate thermocouple and temperature meter. My cheapo meter actually read about 10C higher than the built in one, but the difference was consistent. Possibly the difference was due to the different placement of the two thermocouples?

                  Anyway today I decided to try a different preset profile - Lead Free 2

                  And this one works! So far I have removed a couple of BGAs (28x28mm) and a 30x30mm
                  QFP

                  I also worked out a couple of other things about the machine. Here is another video. Unfortunately I managed to put my finger over the phone microphone for a minute or two but I wasn't saying anything important at the time lol

                  So far it seems this machine is fairly easy to use, just by selecting the built in profiles.

                  To be honest this is proving far easier than I expected.

                  But I only tried component removal so far - maybe soldering components back on is more difficult.

                  https://youtu.be/qI96yDvGmwo

                  Rich
                  Last edited by dicky96; 12-13-2019, 06:02 AM.
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                    #10
                    Re: BGA Station - having some problems with profiles

                    Evidentally my technique for cleaning all the old solder off the PCB under the BGA needs some improvement.

                    On the first one I tried I wondered if the machine had lifted these pads so I looked at the BGA chip under the microscope and the missing pads were not attached there.

                    On the second one I checked everything with the microscope first before cleaning the old solder and it all looked OK until I removed the excess solder from the PCB and I had managed to bend one track/pad over backwards on that one, though I didn't actually lift any pads clean off the board.

                    I'm using a technique I've seen on the internet - cutting a small length of desolder braid 1-2cm long, dipping it in rosin, then sweeping it around the PCB with a chisel tip on my soldering iron. I obviously need more practice or a better way of doing this.

                    Maybe my solder iron is set to the wrong temperature, or I need to use the preheater with the iron

                    .
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                      #11
                      Re: BGA Station - having some problems with profiles

                      Add flux then push a nice ball of leaded solder around the pads, ideally without the tip touching the board. Remove the ball with your iron then use decent braid.

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                        #12
                        Re: BGA Station - having some problems with profiles

                        I'm watching a few more videos

                        Any particular braid recommended? I thought they were all pretty much the same as. Especially when dipped in rosin before use. The braid I have now is Servisol. But I'm happy to try something different.
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                          #13
                          Re: BGA Station - having some problems with profiles

                          No, braids are not created equal. I use Chemtronics, it's pre fluxed and is non scratchy like some of the cheap braids.
                          I've usually clear the old solder whilst the board is still hot and on the rework station. The less thermal cycles the better IMO.

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                            #14
                            Re: BGA Station - having some problems with profiles

                            OK I'll give that a try. Cheers

                            https://www.ebay.co.uk/itm/Chemtroni...IAAOSwa1hdHJen
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                              #15
                              Re: BGA Station - having some problems with profiles

                              To get this thread back onto the original topic

                              I've been playing around with this machine for about a week now. I've been able to successfully remove BGA and large QFP from a number of PCBs and also been able to align and resolder QFP. I tried the alignment on QFP first as it is easy to see if the machine actually placed the chip OK when it looked good on the optical alignment camera. Now I mastered that, I am confident it will also place BGA reliably.

                              I have one really stubborn PCB here that refuses to unsolder anything using the built in profiles

                              Having removed a BGA and a few NAND chips and similar from this board using my hot air station and preheater, I was sure that the chips are not actually glued down, it's just that this particular PCB seems to soak up a lot of heat. The Kada preheater on full after a couple of minutes can't get it above about 140C

                              I copied one of the pre-programmed profiles then set about modifying it and repeatedly trying to desolder a NAND chip from the baord. I then increased the soak time, soak temperature and the peak heat until it actually removed the chip while trying to keep the peak heat as low as I could. After several attempts I got the machine to work on this PCB.

                              However to successfully rework on this board, I am having to take the chip temperature up to 240C after 180 seconds of ramping up, then hold it there for 60 seconds and finally push it up to 257C and hold for another 30 seconds, to get it to unsolder reliably.

                              That is measured on a separate Temperature meter, on the built in one I read abit hotter. The meter says 240C/257CC the G720 built in probe reading says 250C/265C. I don't know which one (if either) is actually accurate maybe I should dip the thermo-couple into boiling water as a reference temperature

                              I did a bit of googling but I couldn't find an actual safe temperature for BGA rework that does not generally damage chips or PCBs. In one youtube video I am sure I saw 235C quoted as the safe maximum. Is ~260C peak too hot?

                              I can't see how I can work on the PCB at lower temperatures

                              Rich
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                              Last edited by dicky96; 12-20-2019, 06:35 AM.
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                                #16
                                Re: BGA Station - having some problems with profiles

                                I go to 240c but I believe 260c is acceptable.

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                                  #17
                                  Re: BGA Station - having some problems with profiles

                                  OK thanks. There are a few NAND blocks left on that PCB so I will now try to reduce the soak and peak temperatures by five degrees at a time until it no longer desolders. I was going up in 10 degree lots before and I did increase the soak time as well so it could be the longer soak is what is making it desolder on this heat sponge of a PCB as much as the higher temps.

                                  It's all good fun, this.
                                  Last edited by dicky96; 12-20-2019, 12:14 PM.
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                                    #18
                                    Re: BGA Station - having some problems with profiles

                                    Yes, I'd give it a longer soak at about 200 before ramping up.

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                                      #19
                                      Re: BGA Station - having some problems with profiles

                                      @diif
                                      I think now is a great time to say thank you for your time spent helping me out on this topic. Merry Christmas to you and yours!

                                      Have a good one.
                                      Last edited by dicky96; 12-24-2019, 03:57 PM.
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                                        #20
                                        Re: BGA Station - having some problems with profiles

                                        You're most welcome.
                                        A Merry Christmas to you too.

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